Re: [musl] PPC64(LE) support in musl requires ALTIVEC

[Romain Naour <romain.naour@gmail.com>]

Hi,

Le 03/02/2020 à 15:50, Rich Felker a écrit :
> On Mon, Feb 03, 2020 at 03:16:17PM +0100, Romain Naour wrote:
>> Hi,
>>
>> We noticed that musl toolchain doesn't work on PPC64 e5500 cpus due to
>> Altived instructions in src/setjmp/powerpc64/setjmp.s [1].
>>
>> A patch has been sent by Vincent Fazio to the Buildroot mailing list to disable
>> musl for such cpus [2].
>>
>> Maybe the supported-platforms list could be updated [3].
>>
>> [1] https://git.musl-libc.org/cgit/musl/tree/src/setjmp/powerpc64/setjmp.s#n74
>> [2] http://patchwork.ozlabs.org/patch/1231986/
>> [3] https://wiki.musl-libc.org/supported-platforms.html
> 
> Is this like the 32-bit Freescale things with the weird alternate FPU?

Indeed, it seems that the only one ppc64 cpu without Altivec support.

> We support those for ppc32 as soft-float (and AIUI the ABI for use
> with the FPU matches soft-float ABI, so in theory it could be
> supported but we were never clear on whether it's IEEE-conforming) but
> I wasn't aware of anything like that for 64-bit so it was never added.
> Assuming it's the same concept, I don't see a reason we couldn't add
> it.

I'm not sure it worth the effort, I don't have a particular interest on this
cpu. I'm fine if this case is not supported.
The issue was discovered by toolchain-builder [1] project (a Buildroot side
project for building cross toolchains) due to issue while testing the system
with Qemu.

If upcoming version of musl support this cpu, we will re-enable musl for it.

[1] https://toolchains.bootlin.com

Best regards,
Romain

> 
> Rich
>